Resilient push dozer



March 8, 1966 J. D. HALL ETAL RESILIENT PUSH DOZER 2 Sheets-Sheet 1 Filed Aug. 27, 1963 NOI (TIN .JAMES D. HALL. BYTHOMAS R. REHBERQ ATTORNEYS March 8, 1966 J. D. HALL ETAI.

RESILIENT PUSH DOZER 2 Sheets-Sheet 2 Filed Aug. 27, 1965 NVENTOR.

JAMES D. HALL. BYTHOMS R. RHBERQ AT TORNEYS United States Patent() 3,238,647 RESILIENT PUSH DOZER James D. Hall, Plainfield, and Thomas R. Rehberg, Chicago Heights, Ill., assignors to Caterpillar Tractor Co., Peoria, lll., a corporation of California Filed Aug. 27, 1963, Ser. No. 304,754 4 Claims. (Cl. 37-144) This invention relates to push dozers which include resilient means to cushion the shock of impact between pushing and pushed machines while they are in motion and particularly to means for rendering the -resilient means ineffective when the dozer blade is used for other purposes.

Tractor mounted bulldozers have heretofore been resiliently mounted to enable them to be more efliciently used in pushing operations. lIt has been common practice to place resilient means behind t-he upper edge of the blade so 4that the lower edge remains relatively rigid for ordinary bulldozing Work when the tractor is not engaged in pushing. While this is an advantage for bulldozing, it is a disadvantage in pushing because when the blade is lowered sufficiently to engage the push blocks of a scraper or other machine in the area of the resilient means on the blade, its lower edge o-ften engages the ground. I-f it is raised from the ground, the cushion behind its upper edge is not fully eflicient.

It is, therefore, the object of the present invention to provide resilient means behind the lower edge Iof a bulldozer blade so that it can be most eiciently used as a push dozer and to provide means to block or lock out the resiliency of such means wlhile the tractor is used for bull dozing.

lFurther and more specific objects and advantages of the invention and the manner in which it is carried into practice are made appa-rent in the following speciiication wherein the invention -is described by reference to the accompanying drawings.

In the drawings:

FIG. 1 is a view in side elevation with parts in section of a resilient pushdozer constructed in accordance with the present invention and showing it mounted upon the forward end of a tractor;

FIG. 2 is a plan view of the elements shown in FIG. 1 with parts broken away; and

FIG. 3 is an enlarged cross section of a portion of one of the resilient links of the present invention.

In FIG. 1, the forward end of a tractor, -generally indicated at 10, supports a blade 11 for use either as a push dozer or a bulldozer. The blade is carried on a substantially parallel linkage comprising a Cframe, generally indicated at 12 (see also FIG. 2) and a pair of resilient links, generally indicated -at 13. The C-fr-ame which is rigid is pivotally connected to the upper edge of the blade by pivots 14 and to the tractor by pivots shown at 15. The links 13 are pivotally connected at their forward end to the lower edge of the blade as at 16 and to the tractor as at 17. A lift jack 18 is pivotally connected to the tractor and to a bracket '-19 extending upward-ly from the C-frame and through a conventional hydraulic system (not shown) may be manipulated to vary the height of the blade 11 with respect to the ground.

Each of the resilient links 13 comprises a rod 20 slid- 3 ,238,647 Patentedv Mar. 8, 1966 ice able within a cylinder 21 containing a spring pack formed of alternately arranged frusto-conical metallic and rubber elements as shown at 22 and 23 respectively (see also FIG. 3). At the end of the cylinder 21 through which the rod enters, a piston-like element or abutment 24 is threadedly secured to the rod ,and `forms a seat for the end of the spring pack. A similarly shaped metallic element 25 is disposed within the spring pack approximately centrally thereof and is slidable with respect to the rod 20 and also with respect to the cylinder 21. This serves to guide the rod for movement coaxially in the cylinder and to prevent cooking movement thereof which would impart undesirable stresses to the head of the cylinder. The head of the cylinder, as best shown in FIG. 3 at 26, contains a spherical type bearing 28 and mating bushing 29 through which the rod slides to provide for self adjustment in the event that slight cooking of the rod does occur. The bearing is held in place by a plate 30 inside of the head .and cap screws 31 as shown. A conventional seal 32 is provided to exclude foreign matter and retain lubricant in the area of the bearing.

With the arrangement shown, the plate 11 may be raised to a position where its lower portion meets a push block .or other member against which pushing force is to be exerted and the resilient links will be directly in line with the point of shock so that their full resiliency is effective when the lower portion of the blade moves rearwardly compressing the resilient members 23 in the cylinder. During absorbing of such shocks, it is necessary for the cylinder to move rearwardly with respect to the rod 20 so that the resilient portion can be compressed between the member 24 on the rod and the opposite end of the cylinder.

When it is desired to eliminate the resilient ee'ct described, means are employed to prevent the necessary movement of the cylinder 21 with respect to fthe rods 20 accomplished by a pair of blocking members 34 which are generally U-shaped in cross section and have a pivotal connection with the tractor coaxial with that of the rod 20 and preferably using the same pins 17 as shown in FIG. 2.

When `resiliency is desired, the blocking members 34 occupy the position shown in lche drawings and when it is desired for the links 13 to be rigid, they .are swung downwardly to the dotted line position indicated at 17a in FIG. 1. In the latter position, the free ends of the blocks lie directly behind the head 26 of the piston to prevent relative movement thereof With respect to the rod. A convenient means for moving the blocking members 34 from -one position `to the other is illustrated as a pair off small hydraulic jacks 35 pivotally connected between the tractor and the blocking members and connected with a controlled source of uid under pressure by means, not shown, and in a conventional manner. Controls for the jacks 35 may be disposed adjacent the tractor operators station for his convenience in quickly changing the links 13 from resilient members to rigid members.

We claim:

1. A resilient push dozer comprising a blade supported forwardly of a tractor on vertically spaced pivoted substantially parallel links, the upper links being rigid and the lower links being resiliently compressible, means to raise and lower the blade about the pivoted parallel connections, `and means selectively operable 4from the dozer 3 operators station to prevent compression of said resilient links.

2. The combination of claim 1 in which the last means comprises a member pivotally connected with respect to the rod `and movable to and away from a position adjacent the end of the cylinder where it blocks relative movement of the rod inwardly of `the cylinder.

3. The combination of claim 1 in which the last means is a U-shaped member pivoted coaxially with lthe rod and movable to a position embracing the rod and extending between the rod pivot and the cylinder head.

4. 'Dhecomlbination Iof claim 3 with hydraulic actuating means to move said U-shaped member toward and away from the cylinder.

References Cited by the Examiner UNITED STATES PATENTS Heinen 37-42 Frink 37-42 Eaton 267-63 X Allen 267-63 X Stand-fuss 37--42 Wills et al 37-144 Kenyon 37-42 Brake 267-1 Rehberg 37-144 ABRAHAM G. STONE, Primary Examiner.

ANTONIO F. GUIDA, Examiner. 

1. A RESILIENT PUSH DOZER COMPRISING A BLADE SUPPORTED FORWARDLY OF A TRACTOR ON VERTICALLY SPACED PIVOTED SUBSTANTIALLY PARALLEL LINKS, THE UPPER LINKS BEING RIGID AND THE LOWER LINKS BEING RESILIENTLY COMPRESSIBLE, MEANS TO RAISE AND LOWER THE BLADE ABOUT THE PIVOTED PARALLEL CONNECTIONS, AND MEANS SELECTIVELY OPERABLE FROM THE DOZER OPERATOR''S STATION TO PREVENT COMPRESSION OF SAID RESILIENT LINKS. 